Network planning for a cellular mobile telecommunications network, such as the GSM or UMTS systems, is a complex task. “The GSM System for Mobile Communications” written and published by M. B. Pautet and M. Mouly, 1992 edition, provides an overview concerning the considerations for network planning.
U.S. Pat. No. 5,960,352 shows a multilayer cellular mobile radio network with optimized frequency re-use plan and a method of optimizing frequency use when adding any microcell base station defining a given microcell that is part of a coverage area of a given macrocell which includes the step of allocating to said microcell a control frequency identical to a traffic frequency used in a macrocell immediately adjacent said given macrocell.
From WO 92/21182 a method is known for optimizing a mobile radio network which is in service, together with a device intended for this. According to that method, it is determined whether an error exists in the network, by monitoring the mobile radio network with an operations and maintenance center. If an error occurs, actual data is retrieved from the mobile radio network in order to calculate nominal data for optimizing the parameter settings in the mobile radio network. The device for carrying out this method is the operations and maintenance center itself.
Australian patent AU-A-20078/97 shows a method for optimising a mobile radio network. In accordance with this proposal a control loop is constructed which contains the operations and maintenance center (OMC) and the processor-controlled device (NPT), which is basically intended for the planning of radio networks. According to this proposal the device, which is a so-called Network Planning Tool, is thereby used as a network optimisation tool.
From the prior art planning solutions for specific capacity, coverage and business needs of a cellular mobile telecommunications network are known. For example the A 956 RNO network optimisation tool chain which is commercially available from Alcatel can be utilized for such purposes. This tool has the ability to determine the geometric contours of cells by using polygons (referred to as “Voronoi” polygons). A variety of other radio network optimisation (RNO) tools is available from other companies.
A common disadvantage of prior art RNO tools is that such tools enable network planning or optimization only at the level of granularity provided by the segmentation of the network into cells (cf. The 2000 GSM World Congress, 2 to 4 Feb. 2000 Cannes, Executive Conference Summary, “Case 1—Planning for Quality when Increasing Network Capacity”, Yves Bellego, France Telecom Mobiles and Phillipe Keryer, Alcatel, France.)